[selectors-4][editorial] Mark some sections explicitly as non-normative, in hopes the normative reference checker is helped

Author: svgeesus

selectors-4/Overview.bs

@@ -88,7 +88,10 @@ Introduction</h2>
 
 		<li>
 			used "in reverse" to generate markup that would match a given selector,
-			such as in <a href="http://haml.info/">HAML</a> or <a href="https://en.wikipedia.org/wiki/Emmet_(software)">Emmet</a>.
+			<span class="non-normative">
+			such as in <a href="http://haml.info/">HAML</a>
+			or <a href="https://en.wikipedia.org/wiki/Emmet_(software)">Emmet</a>
+			</span>.
 	</ul>
 
 	Selectors Levels 1, 2, and 3 are defined as the subsets of selector
@@ -97,7 +100,7 @@ Introduction</h2>
 	<a href="https://www.w3.org/TR/css3-selectors/">Selectors Level 3</a>
 	specifications, respectively. This module defines Selectors Level 4.
 
-<h3 id="placement">Module Interactions</h3>
+<h3 id="placement" class="non-normative">Module Interactions</h3>
 
 	<wpt title="Tests not needed for this section."></wpt>
 
@@ -5093,7 +5096,7 @@ Appendix B: Obsolete but Required <code>-webkit-</code> Parsing Quirks for Web C
 		</details>
 
 
-<h2 id="visited-privacy">
+<h2 id="visited-privacy" class="non-normative">
 Appendix C: Example Privacy-Preserving '':visited'' Restrictions</h2>
 
 Previous attempts to protect user privacy in '':visited''